1. Field of the Invention
The present invention relates to a strand pulling-off method for a metal strand, particularly a steel strip, cast in a curved continuous casting plant, wherein the metal strand is initially vertically pulled from a casting mold, wherein a curved shape is then imparted on the metal strand in a curved entry driver driven with an entry torque, and wherein, after reaching a horizontal strand travel direction, the metal strand is finally straightened in a curved exit driver driven with an exit torque.
2. Description of the Related Art
Strand pulling-off methods of the above-described type are generally known in the art. In these methods, the cast metal strand is bent by means of a driven curved entry driver, also called bending driver, from the vertical into a curved shape. After reaching the horizontal, the metal strand is then once again straightened by means of a driven curved exit driver, also called straightening driver, so that the metal strand leaves the curved continuous casting plant in a horizontal strand travel direction.
In the optimum situation, the strand substantially has the shape of a circular arc between the curved entry driver and the curved exit driver. However, even slight differences in the speeds between the drivers have the result that the metal strand is deflected from its ideal line. The metal strand then either extends in the shape of a chord or the metal strand sags through. Accordingly, the speed differences may lead to difficulties in operating the plant or may even lead to interruptions of the casting operation. In either case, the quality of the cast metal strand is negatively influenced.
The book "StranggieBen von Stahl--Einfuhrung und Grundlagen" [Continuous Casting of Steel--Introduction and Basics] by Hans Schrewe, Verlag Stahleisen mbH, Dusseldorf (Germany) 1987, pages 13 and 46 to 50, discloses a strand pulling-off method for a metal strand, particularly a steel strip, cast in a curved continuous casting plant, wherein the metal strand is initially vertically pulled from a continuous casting mold, a curved shape is then imparted on the metal strand in a curved entry driver, the metal strand is then guided in a multiple-roller drive and the metal strand is straightened in several steps, so that the metal strand leaves the curved continuous casting plant after reaching a horizontal strand travel direction.